Thrombosed Type A Acute Aortic Dissection Quick Overview of a Clinical Variant of Aortic Dissection

Thrombosed type A acute aortic dissection (TA AAD) is a subtype of aortic dissection. The computed tomography shows a crescent-shaped false lumen with neither entry nor blood flow in the false lumen. Clinical characteristics of TA AAD are sometimes different from those of the classical aortic dissection. The worst scenario is the progression to classical aortic dissection, which means recanalization of the false lumen, frank rupture, or aneurysmal formation is worse clinical manifestations. On the other hand, spontaneous regression of the false lumen leading to the disappearance of the aortic dissection is the best course. Optimal strategy for TA AAD still remains debatable. One of the reasons is the international differences in the outcomes of TA AAD. In the Western countries, the patients treated with emergent operation had lower mortality than those treated with medical therapy. On the other hand, in Asian countries, favorable outcomes have been demonstrated in the strategy of medical therapy alone for uncomplicated patients or medical therapy plus timed surgery for complicated patients. On Japanese guidelines for aortic dissection issued in 2011, the surgical treatment for TA AAD is indicated for the patients with cardiac tamponade, aortic regurgitation (AR), large ascending aorta (>50 mm) and thick thrombosed false lumen (>11 mm). The initial medical therapy is selected for patients who do not have the surgical criteria. Once selected, close inspection of the patient and repetitive radiographic follow-up are needed to detect the propagation of aortic dissection rapidly. We should rediscover the fact that thrombosed type A acute aortic dissection belongs to the “acute aortic syndrome” and is likely to progress to the overt aortic dissection or aortic rupture. The optimal selection of the initial treatment according to the risk stratification can improve the outcomes of this unique disease.